/**
 * 高精度减法
 */

#include <iostream>
#include <vector>
#include <bits/stdc++.h>

using namespace std;

bool cmp(vector<int> &A, vector<int> &B) {
    if (A.size() != B.size()) {
        return A.size() > B.size();
    } else {
        for (int i = A.size() - 1; i >= 0; --i) {
            if (A[i] != B[i]) {
                return A[i] > B[i];
            }
        }
    }
    return true;
}

vector<int> sub(vector<int> &A, vector<int> &B) {
    vector<int> C;
    for (int i = 0, t = 0; i < A.size(); ++i) {
        t = A[i] - t;
        if (i < B.size()) {
            t -= B[i];
        }
        C.push_back((t + 10) % 10);
        if (t < 0) {
            t = 1;
        } else {
            t = 0;
        }
    }
    //去掉前导 0 
    while (C.size() > 1 && C.back() == 0) {
        C.pop_back();
    }
    return C;
}

int main() {
    string a, b;
    vector<int> A, B;

    cin >> a >> b;
    for (int i = a.size() - 1; i >= 0; --i) {
        A.push_back(a[i] - '0');
    }
    for (int i = b.size() - 1; i >= 0; --i) {
        B.push_back(b[i] - '0');
    }

    if (cmp(A, B)) {
        auto C = sub(A, B);
        for (int i = C.size() - 1; i >=0; --i) {
            printf("%d", C[i]);
        }
    } else {
        auto C = sub(B, A);
        printf("-");
        for (int i = C.size() - 1; i >=0; --i) {
            printf("%d", C[i]);
        }
    }
    return 0;
}